The flagship feature of PopIn is that your guests don't need to sign up. They get a link, they RSVP, they show up. No app store, no account creation, no password to forget. We say this on every page. It's the headline of the product.
What we don't say as often is how surprisingly hard it is to actually build something this way. Every feature gets evaluated through a lens most products don't have: does this work for someone who doesn't have an account? If it doesn't, the feature is wrong, and it needs to be redesigned.
This post is about a few of those decisions, because they're the kind of things that look obvious in hindsight but were genuinely hard to figure out.
What we mean by "no account required"
Most products that claim no-account guests actually mean "we'll make a temporary account for you behind the scenes and pretend we didn't." That counts for some flows. For PopIn it doesn't.
The bar we set is: a guest can use the link you sent them in a private browser window with cookies disabled, click through the RSVP form, see the event details, get a reminder by email or SMS, and add the event to their calendar, without our system ever asking them to "save" or "claim" anything. Their interaction with PopIn is functionally identical to opening a webpage. We don't trick them into having an account.
The consequence: their relationship with the event is via the link itself. The link is the credential. They can bookmark it, share it (which we made a deliberate choice to limit by default, since guest lists can be sensitive), and come back to it. Closing the tab and reopening it later is the same experience as the first time.
The headcount question
One of the first things hosts ask about no-account guests is: how do we know how many showed up if they didn't sign up? It's a fair question. The answer is: they self-report. When they RSVP, they pick Going / Maybe / Can't make it, just like signed-up users. We don't double-count people who fill out the form twice; the email or phone they used is the dedupe key. If they want to bring a plus-one, that's an additional field on the form.
The thing that surprised us is that no-account guests are more diligent about RSVPing than signed-up ones, not less. The lack of friction makes it easier for them to reply, and there's no notification fatigue distracting them, so they tend to actually do it within a day or two of getting the invite. The original assumption was that they'd be harder to wrangle than signed-in users. The opposite turned out to be true.
Reminders without notifications
Signed-in users get push notifications. No-account guests don't (they're not running the app). So we needed a way to nudge them that didn't depend on them having anything installed. Email and SMS were the obvious answer; the harder question was tone.
You can't just send three emails to a guest list. People hate that. The bar for "useful reminder" vs "annoying spam" is much lower for a guest than for a logged-in user who explicitly opted in to push. We landed on: one initial invitation, one nudge if they haven't responded within 4-7 days, one reminder 24 hours before the event with the address and time, and nothing else. If something changes, the host has a separate broadcast tool to send updates, and those go out via the channel each guest preferred when they RSVPd.
What we gave up
The honest part: not having accounts for guests means we don't have a profile to build on. We don't know if your guest came to other events. We can't show them photos from the night unless they opt in by signing up after the fact. We can't cross-reference them across the platform.
That's a real product cost. There's an alternative-universe version of PopIn that creates ghost profiles for every guest, slowly builds up data on them across events, and eventually shows them a "you've been to 12 PopIn events, sign up to claim your history" wall. That version of PopIn is probably more monetisable.
We chose the other path because it matches the original problem. The whole reason no-account guests exist is that there's a meaningful slice of people who don't want to sign up, period. Building infrastructure that gradually pressures them into signing up is just account-required-with-extra-steps. So we let it go. The cost is real, but it's the right cost to pay for keeping the no-account promise actually honest.